The present invention relates to methods for preparing pigments and to methods for using said pigments.
It is often desirable to provide household toiletries such as soap bars and toothpaste with pleasant colors. Such colors are provided to said toiletries through the use of dyes and pigments. For example, green pigment has been introduced to soap and toothpaste through the addition of chlorophyll to said products. Unfortunately, such a pigment is high in price and is difficult to color match, thus resulting in quality control problems.
It has also been common practice to introduce organic and/or inorganic pigments to soap or toothpaste. For example, green pigment can be introduced to said products via the use of phthalocyanine pigments or via the addition of chromium hydroxide. Although such inorganic pigments are relatively cheap to produce and are fairly simple to color match, such pigments pose potential toxicity problems and/or introduce heavy metals into municipal sewage systems.
In order to avoid the potential toxicity problems introduced to toiletries via the addition or organic and/or inorganic pigments thereto, it would be highly desirable to use government approved food, drug and cosmetic dyes into said toiletries. Unfortunately, such dyes are typically water-soluble and introduce disadvantages when used in coloring soaps and toothpaste. For example, water-soluble dyes will leave an undesirable color on skin, towels, etc. and will often complex with proteinous materials such as skin. In addition, as soap bars are wetted and rewetted, water-soluble dyes will tend to run and consequently stain sinks, bathtubs, etc.
In view of the deficiencies of the prior art, it would be highly desirable to provide a method of coloring toiletries using nontoxic, water-soluble dyes, wherein such dyes are introduced to said toiletries in a water-insoluble, pigment form.